. Bulletin of the British Museum (Natural History) Zoology. <H Fig. 5 Dorso-anterior view of the right palatine in: a. Onychostoma sima b. Scaphesthes barbatulus c. Scaphiodonichthys burmanicus d. Varicorhinus beso e. Barbus barbus. Fig. 6 Ventral view of vomer and palatine in: a. Onychostoma sima b. Scaphiodonichthys burmanicus c. Semiplotus semiplotus lacking in Varicorhinus and Capoeta. In these genera, the dentaries contact one another across a flat symphysial surface and there is no inner ligament (Fig. 8c). The mouth of Onychostoma and Scaphesthes exhibits three external morphotypes.
. Bulletin of the British Museum (Natural History) Zoology. <H Fig. 5 Dorso-anterior view of the right palatine in: a. Onychostoma sima b. Scaphesthes barbatulus c. Scaphiodonichthys burmanicus d. Varicorhinus beso e. Barbus barbus. Fig. 6 Ventral view of vomer and palatine in: a. Onychostoma sima b. Scaphiodonichthys burmanicus c. Semiplotus semiplotus lacking in Varicorhinus and Capoeta. In these genera, the dentaries contact one another across a flat symphysial surface and there is no inner ligament (Fig. 8c). The mouth of Onychostoma and Scaphesthes exhibits three external morphotypes. In type one (Fig. 9a) the mouth width spans that of the head; this type is present in Onychostoma sima, O. elongatus, O. angustistomatus and Scaphesthes macrolepis. In type two (Fig. 9b) the mouth width is greater than that of the head (the corners of the mouth are expanded beyond the lateral margin of the head); it is present in Scaphesthes barbatulus, S. alticorpus, S. lepturus and Ony- chostoma gerlachi. In type three (Fig. 9c) the mouth is moderate to small, its width less than that of the head; this type is present in Onychostoma lini, O. ovalis, O. rhomboides and Scaphes- thes barbatus. Despite these external differences, all these taxa possess the derived osteological structures of the jaws described for Onychostoma laticeps (see above and Howes, 1982). The mouth of Scaphiodonichthys belongs to type two category, but lacks the lateral groove that runs from the snout to the angle of the mouth (Fig. 10) and which is present in Onychostoma and Scaphesthes. The 1st and 2nd infraorbitals entirely cover the maxilla and premaxilla laterally. The adductor mandibulae muscle A! inserts on the posterior tip of the maxilla (Fig. lib). In the majority of cyprinids, includ- ing Onychostoma, Scaphesthes, Varicorhinus, Cyprinion and â¢â Semiplotus, the snout groove is present and the adductor mandibulae muscle A] inserts on a small centrally situated lateral process on the maxilla (F
Size: 2773px × 901px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollection, bookpublisherlondonbutterworths
